Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

An overview of AspectJ

Software systems dealing with distributed applications in changing environments normally require human supervision to continue operation in all conditions. These (re-)configuring, troubleshooting, and in general maintenance tasks lead to costly and time-consuming procedures during the operating phase. These problems are primarily due to the open-loop structure often followed in software development. Therefore, there is a high demand for management complexity reduction, management automation, robustness, and achieving all of the desired quality requirements within a reasonable cost and time range during operation. Self-adaptive software is a response to these demands; it is a closed-loop system with a feedback loop aiming to adjust itself to changes during its operation. These changes may stem from the software system's self (internal causes, e.g., failure) or context (external events, e.g., increasing requests from users). Such a system is required to monitor itself and its context, detect significant changes, decide how to react, and act to execute such decisions. These processes depend on adaptation properties (called self-a properties), domain characteristics (context information or models), and preferences of stakeholders. Noting these requirements, it is widely believed that new models and frameworks are needed to design self-adaptive software. This survey article presents a taxonomy, based on concerns of adaptation, that is, how, what, when and where, towards providing a unified view of this emerging area. Moreover, as adaptive systems are encountered in many disciplines, it is imperative to learn from the theories and models developed in these other areas. This survey article presents a landscape of research in self-adaptive software by highlighting relevant disciplines and some prominent research projects. This landscape helps to identify the underlying research gaps and elaborates on the corresponding challenges.

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Self-adaptive software: Landscape and research challenges

[서평]「Component Software」 - Beyond Object-Oriented Programming -

An aspect observes the execution of a base program; when certain actions occur, the aspect runs some extra code of its own. In the AspectJ language, the observations that an aspect can make are confined to the current action: it is not possible to directly observe the history of a computation.Recently, there have been several interesting proposals for new history-based language features, most notably by Douence et al. and by Walker and Viggers. In this paper, we present a new history-based language feature called tracematches that enables the programmer to trigger the execution of extra code by specifying a regular pattern of events in a computation trace. We have fully designed and implemented tracematches as a seamless extension of AspectJ.A key innovation in our tracematch approach is the introduction of free variables in the matching patterns. This enhancement enables a whole new class of applications in which events can be matched not only by the event kind, but also by the values associated with the free variables. We provide several examples of applications enabled by this feature.After introducing and motivating the idea of tracematches via examples, we present a detailed semantics of our language design, and we derive an implementation from that semantics. The implementation has been realised as an extension of the abc compiler for AspectJ.

/pdf/adding-trace-matching-with-free-variables-to-aspectj-13l2nh50bg.pdf

Adding trace matching with free variables to AspectJ

In this paper we introduce a novel aspect oriented implementation language, called JAsCo. JAsCo is tailored for component based development and the Java Beans component model in particular. The JAsCo language introduces two concepts: aspect beans and connectors. An aspect bean describes behavior that interferes with the execution of a component by using a special kind of inner class, called a hook. The specification of a hook is context independent and therefore reusable. A connector on the other hand, is used for deploying one or more hooks within a specific context. To implement the JAsCo language, we propose a new "aspect-enabled' component model, which contains build-in traps that enable to interfere with the normal execution of a component. The JAsCo component model is backward-compatible with the Java Beans component model. Furthermore, the JAsCo component model allows very flexible aspect application, adaptation and removal at run-time. The necessary tool support for the JAsCo approach has been implemented. In addition, we present a performance assessment of our current implementation.

/pdf/jasco-an-aspect-oriented-approach-tailored-for-component-1mnc52asny.pdf

JAsCo: an aspect-oriented approach tailored for component based software development

Aspect-Oriented Programming in JAsCo

http://ieeexplore.ieee.org/iel5/52/33326/01576656.pdf

Wim Vanderperren

Papers

Aspect-Oriented Programming in JAsCo

aspect- oriented pr ogramming

Automatic Feature Interaction Analysis in PacoSuite.